1. Field of the Invention
The prevent invention relates to an automatic document feeder provided for a copying apparatus, more particularly, to an automatic document feeder capable of serially arranging a pair of documents at a specified position on a platen and ejecting them after the completion of image exposure
2. Description of Related Art
To reduce a time for replacing documents or to eliminate a procedure for document replacement, various copying apparatuses provided with an automatic document feeder (hereinafter abbreviated as ADF) have been recently developed and are commercially available.
Various conventional ADFs, however, feed documents one by one onto a platen. Accordingly, to perform two-document, one sided copying, an operator is supposed to replace documents and place them on the platen per sheet of document, thus time and labor are not reduced.
To avoid such disadvantages, an ADF which is capable of serially arranging two documents onto a platen has been disclosed in Japanese Patent Unexamined Publication No. 60-93462, wherein the second document is fed consecutively to the first document by a document separation device. This document feeding method is called "serial double feeding". However, commercialization of a serial double feeding ADF is difficult due to its unreliability, that is to say, accurate document feeding may not be achieved.